Well... I had a feeling this was coming.

While I don't appreciate that black rat taking my books, I'm pretty much used to it, but...

When I heard she'd taken that book—

The sealed grimoire!?

That idiot carelessly went so deep inside...?

What happened to the concealment spell? It should've been hidden from sight and cognition alike...

The concealment was active, but... Her magical power may have been enhanced by an elixir or catalyst or something.